Hedge trimmer

ABSTRACT

A hedge trimmer includes a first housing with a first handle, a second housing with a second handle, a transmission mechanism combined to the first housing, a trimming blade for being driven by the transmission mechanism to carry out a shearing motion, an electric motor combined to the first housing and for driving the transmission mechanism, and a battery pack combined to the second housing and for supplying power to the electric motor. The first and second housings respectively include first and second rotation connection parts for making them be connected and rotatable around a rotation axis. The second housing has first and second rotation positions when being rotated with respect to the first housing. A plane perpendicular to the rotation axis is obliquely intersected with a plane perpendicular to a longitudinal axis of the trimming blade.

RELATED APPLICATION INFORMATION

This application claims the benefit of and is a continuation of U.S.application Ser. No. 15/262,681, filed on Sep. 12, 2016, whichapplication claims the benefit of CN 201510587038.8, filed on Sep. 15,2015, CN 201510583676.2, filed on Sep. 15, 2015, CN 201510582764.0,filed on Sep. 15, 2015, and CN 201510586701.2, filed on Sep. 15, 2015,the disclosures of which are incorporated herein by reference in theirentirety.

BACKGROUND

This following disclosure relates to a hedge trimmer.

A hedge trimmer is a kind of garden or gardening tool and includes atrimming blade, a front handle and a rear handle. The trimming blade iscapable of carrying out reciprocating motion to cut a variety of shrubs,hedges and so on. In a trimming process, the user grasps the twodifferent handles by two hands respectively, and the user then controlsa position of the trimming blade by moving the handles to control thecutting position.

The structure of a housing of the traditional hedge trimmer isrelatively fixed, the positions of the front and rear handles cannot beadjusted and thus it is not able to work efficiently under complexworking conditions. It is only suitable for simple cutting in horizontalplane, when there is a need of vertical cutting or oblique cutting, itis difficult to operate and is very inconvenient for the two hands togrip the handles.

The housing of the traditional hedge trimmer is generally made of asingle material, and its heat dissipating effect is relatively poor.After working for a long time, the temperature would be excessively highand therefore it is easy to cause damage of the hedge trimmer.

For a traditional electric motor, in order to reduce the temperature ofthe electric motor and accelerate cooling, a cooling fan is equipped.However, when the cooling fan is rotating, the phenomenon of airflowspinning around the inside the casing of the electric motor can resultin poor cooling effect.

SUMMARY

A hedge trimmer includes a trimming blade that extends along alongitudinal axis and configured (i.e., structured and arranged) forcarrying out reciprocating motion, a first housing, being formed orconnected with a first handle and disposed with a first locking portion,a second housing, being formed or connected with a second handle androtatable with respect to the first handle around a rotation axiswherein a plane perpendicular to the rotation axis is obliquelyintersected with a plane perpendicular to the longitudinal axis of thetrimming blade, a transmission mechanism, being combined to the firsthousing and for driving the trimming blade, an electric motor, beingcombined to the first housing and for driving the transmissionmechanism, a battery pack, being combined to the second housing and forsupplying the electric motor with electric power, a trigger, configuredfor controlling the electric motor, and a control member, being movablyconnected to the first housing or the second housing and including astopper portion and a second locking portion matched with the firstlocking portion. The control member has a first position and a secondposition with respect to the second housing. When the control member isat the first position, the first locking portion and the second lockingportion are engaged with each other, the second housing and the firsthousing are relatively fixed. When the control member is at the secondposition, the stopper portion stops movement of the trigger, the firstlocking portion and the second locking portion are disengaged with eachother, and therefore the second housing is allowed to rotate withrespect to the first housing around the rotation axis.

The first locking portion may be formed with a recess, and the secondlocking portion is formed with a protrusion matched with the recess.

The control member may further include a manipulating portion configuredto enable the control member to move between the first position and thesecond position. The manipulating portion is located between the secondhandle and the battery pack.

The hedge trimmer may further include a biasing member connected to thesecond housing and for applying a biasing force to enable the controlmember to move from the second position to the first position.

The control member may be capable of sliding between the first positionand the second position along a linear path.

The hedge trimmer may further include a damping member. The dampingmember is disposed between a first rotation connection part of the firsthousing and a second rotation connection part of the second housing.

The first housing may be disposed with a plurality of recesses forfacilitating the control member to lock a relative position of the firsthousing and the second housing. As far as the circumferential directionof the rotation axis is concerned, an angle difference of adjacent onesof the plurality of recesses is 15° or an integer times of 15°.

The second housing may have a first rotation position and a secondrotation position with respect to the first housing. When the secondhousing is rotated to the first rotation position, a plane in which alongitudinal axis of the second handle locates is parallel to thelongitudinal axis of the trimming blade. When the second housing isrotated to the second rotation position, the second handle is rotatedwith 90 degrees with respect to the first rotation position.

The second housing may be rotated to the second rotation position, thesecond handle and the battery pack respectively are located at two sidesof a plane defined by an intersection of an axis of the electric motorwith the longitudinal axis of the trimming blade.

The rotation axis and an axis of the electric motor are obliquelyintersected.

The hedge trimmer may also include a first housing, formed or connectedwith a first handle and disposed with a first rotation connection part,a second housing, formed or connected with a second handle and disposedwith a second rotation connection part being connected with the firstrotation connecting part and rotatable around a rotation axis between afirst rotation position and a second rotation position with respect tothe first rotation connection part wherein a plane perpendicular to therotation axis and a plane perpendicular to a longitudinal axis of atrimming blade are obliquely intersected, a transmission mechanism,combined to the first housing, a trimming blade, configured for beingdriven by the transmission mechanism to carry out a shearing motion, anelectric motor, combined to the first housing and configured for drivingthe transmission mechanism, and a battery pack, combined to the secondhousing and configured for supplying power to the electric motor.

In the plane perpendicular to the longitudinal axis of the trimmingblade, the first rotation connection part and the electric motor may belocated at a same side of the trimming blade.

In the plane perpendicular to the longitudinal axis of the trimmingblade, the first rotation connection part and the first handle may belocated at a same side of the trimming blade.

When the second housing is rotated to the first rotation position, aplane in which a longitudinal axis of the second handle locates may beparallel to the longitudinal axis of the trimming blade. When the secondhousing is rotated to the second rotation position, the second handle isrotated 90 degrees with respect to the first rotation position.

The second handle may have a midsplit plane, and the second handle is atleast partly symmetrical with respect to the midsplit plane. When thesecond housing is rotated to the first rotation position, the midsplitplane of the second handle is parallel to the longitudinal axis of thetrimming blade.

Also, the second handle may have a midsplit plane, the second handleincludes a main handle portion for facilitating a user to grip, and themain handle portion is disposed symmetrical with respect to the midsplitplane. When the second housing is at the second rotation position, inthe midsplit plane, the main handle portion and a center of gravity ofthe battery pack respectively are located at two sides of thelongitudinal axis of the trimming blade.

When the second housing is rotated to the first rotation position, in adirection parallel to the longitudinal axis of the trimming blade, thesecond handle may be rotated to the nearest position distant from thefirst handle. When the second housing is rotated to the second rotationposition, a distance between the second handle and the first handle isgreater than a distance between the second handle and the first handlewhen the second housing is rotated to the first rotation position.

When the second housing is rotated to the second rotation position, thesecond handle and the battery pack may be respectively located at twosides of the longitudinal axis of the trimming blade.

When the second housing is rotated to the second rotation position, thesecond handle and a center of gravity of the battery pack may berespectively located at two sides of a midsplit plane of the front orfirst handle.

When the second housing is rotated to the second rotation position, thesecond handle and the battery pack may be respectively located at twosides of a plane defined by intersection of an axis of the electricmotor with the longitudinal axis of the trimming blade.

The hedge trimmer may also include an electric motor including a statorassembly and a rotor assembly, a transmission mechanism for being drivenby the electric motor, a trimming blade for being driven by thetransmission mechanism to perform shearing motion, an electric motorcasing for accommodating the rotor assembly of the electric motor, and atool housing assembly for facilitating the transmission mechanism andthe electric motor casing to be formed into a whole. The tool housingassembly includes a first material part which at least is made of afirst material. The electric motor casing includes a second materialpart which at least is made of a second material. The second materialpart is at least partly exposed outside the tool housing assembly.

The hedge trimmer may further include a transmission casing foraccommodating the transmission mechanism. The transmission casing isexposed outside the tool housing assembly.

The transmission casing may be at least partly made of a metal material.

The second material part may be exposed outside the tool housingassembly from one side, and the transmission casing being exposedoutside the tool housing assembly from the opposite side.

The transmission casing may include a transmission casing main bodyformed with an accommodating chamber and a plurality of transmissioncasing ribs outwardly protruding from the transmission casing main body.Each two transmission casing ribs forming an airflow channeltherebetween.

The airflow channel may extend substantially along a direction parallelto an axis of the electric motor.

The electric motor casing may be disposed with a fan therein. Theelectric motor casing is formed with air outlets. Airflow produced bythe fan enters into the electric motor casing from the airflow channeland then is exhausted out from the air outlets.

The tool housing assembly may be disposed with a circuit board therein.The tool housing assembly is formed with an air inlet. Airflow producedby the fan sequentially flows through the air inlet, the circuit board,the electric motor and the air outlets.

The hedge trimmer may further include a first handle located between thetrimming blade and the electric motor. The first handle is fixed to thetransmission casing.

The hedge trimmer may further include a battery pack for supplying powerto the electric motor. The tool housing assembly includes a firsthousing and a second housing. The first housing is formed or connectedwith a first handle. The second housing is formed or connected with asecond handle. The battery pack is combined to the second housing. Thefirst housing and the second housing respectively include a firstrotation connection part and a second rotation connection part formaking them be rotatably connected and take a rotation axis as an axis.The second housing has a first rotation position and a second rotationposition during being rotated with respect to the first housing. A planeperpendicular to the rotation axis and a plane perpendicular to alongitudinal axis of the trimming blade are obliquely intersected.

In the plane perpendicular to the longitudinal axis of the trimmingblade, the first rotation connection part and the electric motor may belocated at a same side of the trimming blade.

An electric motor device includes an electric motor casing formed withair outlets, a stator assembly, fixedly connected with the electricmotor casing, a rotor assembly, rotatably connected with the statorassembly, a fan, disposed inside the electric motor casing, and a windguide hood, accommodated in the electric motor casing. The wind guidehood includes airflow shield portions for stopping airflow produced bythe fan spinning around inside the electric motor casing. The airflowshield portions are disposed between an inner wall of the electric motorcasing and the fan.

The rotor assembly drives the fan to rotate. The airflow shield portionsand the air outlets may be staggeredly arranged in the circumferentialdirection of an axis of rotation of the fan.

The airflow shield portions and the air outlets may be generally alignedin an axial direction of an axis of rotation of the fan.

The number of the airflow shield portions may be greater than or equalto 2, and at least two of the plurality of airflow shield portions aredisposed with the air outlet therebetween.

The number of the airflow shield portions may greater than or equal to2, and at least two of the a plurality of airflow shield portions aresymmetrical with respect to an axis of rotation of the fan.

The wind guide hood may further include a connecting portion connectedwith the plurality of airflow shield portions and a surrounding portiondisposed surrounding the rotor assembly. The surrounding portion and theconnecting portion respectively are located two sides of the fan.

The surrounding portion may be formed with a buckle, and the buckle isconnected with the electric motor casing.

A gap between the surrounding portion and the electric motor may begreater than or equal to 0.3 mm and smaller than or equal to 3 mm.

The hedge trimmer may include any one of the above electric motordevices.

The hedge trimmer may further include a first housing and a secondhousing. The first housing is formed or connected with a first handle.The second housing is formed or connected with a second handle. Thebattery pack is combined to the second housing and for supplying powerto outer rotor electric motor. The first housing and the second housingrespectively include a first rotation connection part and a secondrotation connection part for making them be connected and rotatablearound a rotation axis. The second housing has a first rotation positionand a second rotation position during being rotated with respect to thefirst housing. A plane perpendicular to the rotation axis is obliquelyintersected with a plane perpendicular to the longitudinal axis of thetrimming blade.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary hedge trimmer.

FIG. 2 is a schematic view of the hedge trimmer in FIG. 1 after a partof the housing is removed.

FIG. 3 is a schematic view of a second housing of the hedge trimmer inFIG. 1 being at a first rotation position.

FIG. 4 is a schematic view of the second housing of the hedge trimmer inFIG. 1 being at a second rotation position.

FIG. 5 is another perspective view of the second housing of the hedgetrimmer in FIG. 1 being at the second rotation position.

FIG. 6 is a partial exploded view of the hedge trimmer in FIG. 1.

FIG. 7 is a schematic view of a control member of the hedge trimmer inFIG. 1 being at a first position.

FIG. 8 is a schematic view of the control member of the hedge trimmer inFIG. 1 being at a second position.

FIG. 9 is a schematic view of airflow associated with the hedge trimmerin FIG. 1.

FIG. 10 is a cross-sectional view of the hedge trimmer in FIG. 1.

FIG. 11 is an exploded view of a part of structure of the hedge trimmerin FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a hedge trimmer 100 includes a trimming blade 10, atransmission mechanism 20, an electric motor 30, a battery pack 40, atool housing assembly 50, a first handle 60 and a second handle 70.

The trimming blade 10 is configured to perform a shearing movement so asto achieve a tool function. The trimming blade 10 extends substantiallyalong one direction, a size of the trimming blade 10 in the direction ismuch greater than its sizes in the other directions, and the directionis defined as the lengthwise direction of the trimming blade 10. Asillustrated in FIG. 1, the trimming blade 10 defines a longitudinal axisS1, and the longitudinal axis S1 is parallel to the lengthwise directionof the trimming blade 10.

A main body of the trimming blade 10 substantially extends along thelongitudinal axis S1. A plurality of (i.e., more than one) cutting edges11 are formed at opposite sides of the main body of the trimming blade10 and each of the plurality of cutting edges 11 protrudes from the mainbody of the trimming blade 10 along a direction perpendicular to thelongitudinal axis S1. A size in the direction perpendicular to thelongitudinal axis S1 is a width of the trimming blade 10.

A size of the trimming blade 10 in another direction perpendicular tothe longitudinal axis S1 is relatively small, so that the trimming blade10 is a substantially laminar structure.

Generally speaking, the cutting edges 11 may be disposed at one side ofthe longitudinal axis S1 of the trimming blade 10, or may be disposed attwo sides of the longitudinal axis S1 of the trimming blade 10. Inparticular, as shown in FIG. 1, the cutting edges 11 extend outwardlyfrom the two sides of the longitudinal axis S1.

The transmission mechanism 20 is connected with the trimming blade 10and for driving the trimming blade 10 to do reciprocating motion. Atransmission casing 21 accommodates the transmission mechanism 20therein. Herein, accommodating the transmission mechanism 20 meansaccommodating all of the transmission mechanism 20 or accommodating apart of the transmission mechanism 20.

The electric motor 30 is connected with the transmission mechanism 20for driving the transmission mechanism 20.

The battery pack 40 is for supplying the electric motor 30 with electricpower. The battery pack 40 for example includes a plurality ofrechargeable battery cells.

The tool housing assembly 50 is for assembling various parts of thehedge trimmer 100 into a whole and includes a first housing 51 and asecond housing 52.

The first housing 51 is formed or connected with the first handle 60,the second housing 52 is formed or connected with the second handle 70,the first handle 60 and the second handle 70 each are for being grippedin one hand by the user, i.e., the first handle 60 is for the user togrip by one hand, and the second handle 70 is for the user to grip bythe other hand. Herein, the term “formed” means the handle is a part ofthe housing, and the term “connected” means directly or indirectlyconnected, i.e., the handle is directly connected to the housing or thehandle is indirectly connected to the housing by other structure. InFIG. 1, the transmission mechanism 20 and the electric motor 30 arecombined to the first housing 51, i.e., the transmission mechanism 20and the electric motor 30 are fixed relative to the first housing 51,they may be directly fixed to the first housing 51, or indirectlyfixedly connected to the first housing 51 via other structure. Moreover,the second housing 52 is formed with the second handle 70, and thebattery pack 40 is removably/detachably connected to the second housing52. The first handle 60 is an individual/separate part and locatedbetween the trimming blade 10 and the electric motor 30. In particular,as shown in FIG. 2, in the direction of the longitudinal axis S1 of thetrimming blade 10, the first handle 60 is located between the trimmingblade 10 and the electric motor 30. The first handle 60 is fixed to thetransmission casing 21. Generally speaking, for a traditional hedgetrimmer 100, its first handle 60 is fixed to the tool housing assembly50, after working for a long time, the trimming blade 10 would producewobble relative to the tool housing assembly 50, the operator grips thefirst handle 60 fixed onto the tool housing assembly 50, the firsthandle 60 would produce wobble relative to the trimming blade 60, whichwould interfere with the use of tool for the user and affect cuttingaccuracy. Because when the user grips the tool, a total weight isapplied onto the first handle 60 by the tool housing assembly 50, thewobble of the tool housing assembly 50 would greatly affect the servicelife of the tool. By fixing the first handle 60 to the transmissioncasing 21 as proposed herein, it can avoid the wobble between thetrimming blade 10 and the first handle 60, meanwhile most of the weightis directly applied onto the first handle 60 by the transmissionmechanism 20, service life of the tool is increased consequently.

As illustrated in FIG. 3, the first housing 51 includes a first rotationconnection part 511, the second housing 52 includes a second rotationconnection part 521, the first rotation connection part 511 and thesecond rotation connection part 521 are rotatably connected and therebythe first housing 51 and the second housing 52 can rotate along arotation axis S2. When the first housing 51 and the second housing 52are rotated with respect to each other, the electric motor 30, thetransmission mechanism 20, the first handle 60 and the first housing 51together are rotated with respect to the second housing 52, the batterypack 40, the second handle 70 and the second housing 52 together arerotated with respect to the first housing 51.

A plane A perpendicular to the rotation axis S2 and a plane Bperpendicular to the longitudinal axis S1 of the trimming blade 10 areobliquely intersected with each other. The plane A perpendicular to therotation axis S2 and the plane B perpendicular to the extendingdirection of the trimming blade 10 are obliquely intersected with eachother. Furthermore, the rotation axis S2 and the trimming blade 10 areobliquely intersected. Specifically, the plane A perpendicular to therotation axis S2 and the plane B perpendicular to the longitudinal axisS1 of the trimming blade 10 are intersected with an angle of 15°. Theangle may be greater than or equal 10° and smaller than or equal to 45°.

In the plane B perpendicular to the longitudinal axis S1 of the trimmingblade 10, the first rotation connection part 511 and the electric motor30 are located at a same side of the trimming blade 10, i.e., the firstrotation connection part 511 is away from the longitudinal axis S1 ofthe trimming blade 10. Specifically, an intersection point of therotation axis S2 between the first rotation connection part 511 and thesecond rotation connection part 521 is deviated from the longitudinalaxis S1 of the trimming blade 10.

In the plane B perpendicular to the longitudinal axis S1 of the trimmingblade 10, the first rotation connection part 511 and the first handle 60are located at a same side of the blade of the hedge trimmer 100. Thefirst rotation connection part 511 and the first handle 60 are locatedat a same side of the trimming blade 10 such that the first rotationconnection part 511 and a gripping portion of the first handle 60 arelocated at the same side of the trimming blade 10. The trimming blade 10defines a shearing plane, and the first rotation connection part 511 andthe electric motor 30 are located at a same side of the shearing plane.The first rotation connection part 511 and the first handle 60 arelocated at a same side of the shearing plane.

The rotation axis S2 and an axis S3 of the electric motor 30 areobliquely intersected. An intersection point of the rotation axis S2with the axis S3 of the electric motor 30 and the second rotationconnection part 521 are located at a same side of the trimming blade 10.A distance from the intersection point of the rotation axis S2 betweenthe first rotation connection part 511 and the second rotationconnection part 521 to the trimming blade 10 is greater than a distancefrom the intersection point of the rotation axis S2 with the axis S3 ofthe electric motor 30 to the trimming blade 10. A distance from theintersection point of the rotation axis S2 with the axis S3 of theelectric motor 30 to the longitudinal axis S1 of the trimming blade 10is greater than or equal to 20 mm and smaller than or equal to 60 mm. Adistance from the intersection point of the rotation axis S2 between thefirst rotation connection part 511 and the second rotation connectionpart 521 to the longitudinal axis S1 of the trimming blade 10 is greaterthan or equal to 30 mm and smaller than or equal to 70 mm.

The plane A perpendicular to the rotation axis S2 and the plane Bperpendicular to the longitudinal axis S1 of the trimming blade 10 areobliquely intersected, so that when the second housing 52 is rotatedwith an angle of 90° relative to the first housing 51, as illustrated inFIG. 4, the battery pack 40 can be away from the trimming blade 10,which can avoid interference with the work in the course of workingresulting from excessively large volume of the battery pack 40 as wellas can avoid damage to the battery pack 40.

The second housing 52 has a first rotation position and a secondrotation position with respect to the first housing 51. The firstrotation position is shown in FIG. 3, and the second rotation positionis shown in FIG. 4 and FIG. 5. The first rotation position acts as aninitial position of the second housing 52, i.e., the most commonly usedworking position of the hedge trimmer 100. As to the first rotationposition, at this situation, a plane in which a longitudinal axis S4 ofthe second handle 70 locates is parallel to the longitudinal axis S1 ofthe trimming blade 10, the term “parallel” herein includes thelongitudinal axis S1 of the trimming blade 10 being located in the planein which the longitudinal axis S4 of the second handle 70 locates.

The second handle 70 includes a main handle portion configured (i.e.,structured and arranged) for facilitating the user to grip and controlthe hedge trimmer 100. When the user uses the second handle 70 and gripsthe main handle portion, the user can touch buttons and switchesdisposed in the vicinity thereof. More specifically, the main handleportion is symmetrical with respect to a plane, and such plane isdefined as an equatorial plane (also referred to as midsplit plane) C ofthe second handle 70. The second handle 70 may be disposed symmetricalwith respect to the equatorial plane C, or may be disposed partlysymmetrical relative to the equatorial plane C. The mirror-symmetricalportion of the second handle 70 may include but not be limited to themain handle portion. The longitudinal axis S4 of the second handle 70 islocated in the equatorial plane C of the second handle 70.

When the second housing 52 is rotated to the second rotation position,the second handle 70 is rotated 90 degrees relative to the firstrotation position. Moreover, the second housing 52 may be rotated withrespect to the first housing 51 and fixed to different positions to meetuser's requirements in a variety of working environments. As far as thecircumferential direction of the rotation axis S2 is concerned, an angledifference between adjacent rotation positions is set to be 15° or aninteger times of 15°. When the second handle 70 is rotated 90° itreaches the second rotation position and can satisfy the need of theuser to carry out vertical trimming.

When the second housing 52 is at the first rotation position, in thedirection parallel to the longitudinal axis S1 of the trimming blade 10,the second handle 70 is rotated to the nearest position distant from thefirst handle 60. When the second housing 52 is rotated to the secondrotation position, a distance between the second handle 70 and the firsthandle 60 is greater than a distance between the second handle 70 andthe first handle 60 when the second housing 52 is rotated to the firstrotation position.

When it is at the second rotation position, a distance of the firsthandle 60 relative to the second handle 79 is greater than the distancewhen it is at the first rotation position. The rotation axis S2 isinclined to the trimming blade 10, after the second housing 52 isrotated, the distance between the first handle 60 and the second handle70 is increased, which makes the user be more comfortable for grippingthe second handle 70 after being rotated.

The longitudinal axis S4 of the second handle 70 is in the equatorialplane C of the second handle 70. The symmetric plane of the secondhandle 70 is the equatorial plane C of the second handle 70.

As illustrated in FIG. 5, when the second housing 52 is at the secondrotation position, in the plane in which the longitudinal axis S4 of thesecond handle 70 locates, the second handle 70 and a center of gravityof the battery pack 40 respectively are located at two sides of thelongitudinal axis S1 of the trimming blade 10.

The plane in which the longitudinal axis S4 of the second handle 70locates is the equatorial plane C of the second handle 70. Moreover,when it is at the second rotation position, the second handle 70 and thebattery pack 40 respectively are located at two sides of thelongitudinal axis S1 of the trimming blade 10. Specifically, the secondrotation position is a position of being rotated with 90° relative tothe first rotation position.

When it is at the second rotation position, the second handle 70 and thecenter of gravity G of the battery pack 40 respectively are located attwo sides of the equatorial plane of the first handle 60. The firsthandle 60 at least includes a mirror-symmetrical portion, and asymmetric plane defined by the portion is the equatorial plane of thefirst handle 60.

When it is at the second rotation position, the second handle 70 and thebattery pack 40 respectively are located at two sides of a plane definedby intersection of the axis of the electric motor 30 and thelongitudinal axis S1 of the trimming blade 10.

As illustrated in FIG. 6, the second housing 52 can be rotated aroundthe rotation axis S2 with respect to the first housing 51, and the firsthousing 51 includes a first locking portion 5111. The first lockingportion 5111 may be formed by the first rotation connection part 511.

The hedge trimmer 100 further includes a control member 91, and thecontrol member 91 is for locking a position of the second housing 52relative to the first housing 51. The control member 91 includes asecond locking portion 911, and the second locking portion 911 ismatched with the first locking portion 5111. The control member 91 ismovably connected to the first housing 51 or the second housing 52. Inparticular, the control member 91 is movably connected to the secondhousing 52. The control member 91 has a first position and a secondposition with respect to the second housing 52, and furthermore thecontrol member 91 and the second housing 52 together are rotatable withrespect to the first housing 51.

As illustrated in FIG. 7, when the control member 91 is at the firstposition, the first locking portion 5111 and the second locking portion911 are engaged with each other, and the second housing 52 is fixed tothe first housing 51, i.e., the second housing 52 cannot be rotatedaround the rotation axis S2 with respect to the first housing 51.

As illustrated in FIG. 8, when the control member 91 is at the secondposition, the first locking portion 5111 and the second locking portion911 are disengaged, and therefore the second housing 51 is allowed torotate around the rotation axis S2 with respect to the first housing 51.

The hedge trimmer 100 further includes a trigger 80 for controlling theelectric motor 30.

The control member 91 includes a stopper portion 912, as shown in FIG.8, when the control member 91 is at the second position. The stopperportion 912 stops the movement of the trigger 80. In FIG. 8, the trigger80 is blocked by the stopper portion 912 and thus cannot upwardly move.When the second housing 52 is allowed to rotate with respect to thefirst housing 51, it can avoid the electric motor to be started bymistaken manipulation and thus have relatively high safety performance.In FIG. 7, when the control member 91 is at the first position, thetrigger 80 can be started, and the position shown in the drawing is theposition of the trigger 80 being pressed to start.

The control member 91 further includes a manipulating portion 913. Theuser can manipulate the manipulating portion 913 to enable the controlmember 91 to move between the first position and the second position.The first locking portion 5111 is formed with a recess 5112, and thesecond locking portion 911 is formed with a protrusion 9111 matched withthe recess 5112. The engagement of the protrusion 9111 with the recess5112 realizes the locking. When the user manipulates the control member91, the control member 91 is moved to the first position, the protrusion9111 of the second locking portion 911 is located in the recess 5112 ofthe first locking portion 5111. The first locking portion 5111 and thesecond locking portion 911 cannot be rotated with respect to each other,i.e., the first housing 51 and the second housing 52 cannot producerelative rotation. When the user manipulates the control member 91 tomake it be moved to the second position, the protrusion 911 and therecess 5112 at this time are disengaged, i.e., they cannot block therelative rotation between the first housing 51 and the second housing52. As illustrated in FIG. 6, the number of the recess 5112 is multiple,and each recess 5112 is corresponding to one relative position of thefirst housing 51 and the second housing 52. As illustrated in FIG. 6,the number of the recesses 5112 is eight , and the eight recesses 5112are respectively corresponding to eight angles, for example, 0°, −45°,45°, −135°, 135°, −90°, 90° and ±180° at a circumferential directionaround the rotation axis S2.

As illustrated in FIG. 7 and FIG. 8, the manipulating portion 913 islocated between the second handle 70 and the battery pack 40. Moreover,the trigger 80 and the manipulating portion 913 are located at a sameside of the second handle 70, and the reasonable use of space canachieve compact structure.

The hedge trimmer 100 further includes a biasing member 92 fixedlyconnected to the second housing 52 and for applying a biasing force toenable the control member 91 to move from the second position to thefirst position. The biasing member 92, as a member for generatingbiasing force, may be a spring, a magnet and so on. In the illustratedembodiment, the biasing member 92 is a spring and is connected to thesecond housing 52 and the control member 91, so as to ensure that whenthe control member 91 is at the first position the control member 91 canbe kept at the first position, and therefore avoid the user's mistakenmanipulation to cause the generation of relative rotation between thefirst housing 51 and the second housing 52.

The control member 91 is capable of sliding between the first positionand the second position along a linear path. The control member 91 hasadvantages of simple operation, short sliding path and quick operation.

As illustrated in FIG. 6, the hedge trimmer 100 further includes adamping member 53, and the damping member 53 is disposed between thefirst rotation connection part 511 and the second rotation connectionpart 521. The trimming blade 10 and the electric motor 30 are fixed tothe first housing 51 and would produce vibration during working, thedamping member 53 can effectively reduce the vibration delivered to thesecond housing 52, so that the vibration on the second handle 70 isreduced and it is comfortable for user to operate.

The first housing 51 is disposed with a plurality of gear structures toenable the control member 91 to lock a relative position of the firsthousing 51 and the second housing 52. As far as the circumferentialdirection of the rotation axis S2 is concerned, an angle difference ofsuccessive gear structures is 15° or an integer times of 15°, i.e., thesecond housing 52 can be locked to an angle of 15° or an integer timesof 15° with respect to the first housing 51.

As illustrated in FIG. 9, the hedge trimmer 100 further includes anelectric motor casing 33, and the electric motor casing 33 accommodatesthe electric motor 30 therein. The tool housing assembly 50 includes afirst material part 54, and the first material part 54 at least is madeof a first material. As shown in FIG. 9, the first housing 51 includesthe first material part 54. The electric motor casing 33 includes asecond material part 331, and the second material part 331 at least ismade of a second material. The first material part 54 may be the wholeof the tool housing assembly 50, or may be a part of the tool housingassembly 50. The first housing 51 may be made of the first material. Athermal conductivity of the first material is low, and a thermalconductivity of the second material is high, that is, the thermalproperty of the second material is stronger than the thermal property ofthe first material. The first material part 54 is made of the firstmaterial with low thermal conductivity, and the second material part 331is made of the second material with high thermal conductivity. Morespecifically, the first material is plastic, and the second material ismetal.

The second material part 331 is at least partially exposed outside thetool housing assembly 50, i.e., all or a part of the second materialpart 331 is exposed outside the tool housing assembly 50, or the secondmaterial part 331 protrudes out of or pierces the tool housing assembly50.

The tool housing assembly 50 of a commonly used hedge trimmer 100directly wraps the electric motor 30 and is made of one material such asplastic, however the plastic has a low thermal conductivity and thus theheat dissipating effect is poor. The electric motor 30 is located in theplastic material, so that it is easy to cause damage of the electricmotor 30 resulting from excessively high temperature. For the purpose ofheat dissipating, the tool housing assembly 50 is formed as a metalpiece, which would lead to the whole weight is large, the hedge trimmer100 as a kind of handheld tool, it is not easy for the operator to carryand manipulate if its weight is excessively large.

Accordingly, the tool housing assembly 50 in the illustrated embodimentdoes not directly wrap the electric motor 30 and the individual electricmotor casing 33 is disposed to accommodate the electric motor 30therein. Moreover, the electric motor casing 33 adopts a material withhigh thermal conductivity, and thus can rapidly dissipate heat generatedfrom the electric motor 30 and thereby reduce the temperature of theelectric motor 30. The tool housing assembly 50 employs a material withlow thermal conductivity to achieve thermal insulation effect and avoiddamage to the human body caused by high temperature. The second materialpart 331 of the electric motor casing 33 is exposed outside or protrudesout of the tool housing assembly 50, which can increase contact area ofthe second material part 331 with air and thereby accelerate heatdissipation of the electric motor 30.

The transmission casing 21 is exposed outside the tool housing assembly50. The phase “exposed outside” means at least partly locates outsidethe tool housing assembly 50. As a result, compact structure isrealized, the volume of the tool housing assembly 50 is reduced and theweight is also reduced, which facilitate the user to carry.

The transmission casing 21 is at least partly made of a metal material.The transmission casing 21 made of the metal material can accelerateheat dissipation, and is in favor of lowering the temperature of thehedge trimmer 100. The transmission casing 21 is exposed outside thetool housing assembly 50, which can increase the contact area with theair and thereby improve cooling effect.

The second material part 331 is exposed outside the tool housingassembly 50 from one side, and the transmission casing 21 is exposedoutside the tool housing assembly 50 from the opposite side. Or, theelectric motor casing 33 and the transmission casing 21 protrude out ofthe tool housing assembly 50 from opposite sides of the tool housingassembly 50. In particular, as illustrated in FIG. 9, the electric motorhousing 33 and the transmission casing 21 protrude out of the firsthousing 51 from opposite sides of the first housing 51.

In FIG. 9, the transmission casing 21 includes a transmission casingmain body 211 and transmission casing ribs 212. As illustrated in FIG.10, the transmission housing main body 211 is formed with anaccommodating chamber 2111, and the accommodating chamber 2111accommodates/receives the transmission mechanism 20 therein. As shown inFIG. 9, a plurality of transmission casing ribs 212 are formedprotruding outwardly from the transmission casing main body 211, andeach two adjacent transmission casing ribs 212 form an airflow channeltherebetween. In particular, the airflow channel 2121 extendssubstantially along a direction parallel to the axis of the electricmotor 30. That is, airflow can flow from the side of the transmissioncasing 21 being located to the side of the electric motor casing 33being located along the airflow channel 2121.

As illustrated in FIG. 9 through FIG. 11, the electric motor casing 33has a fan 34 disposed therein. The electric motor casing 33 is formedwith air outlets 332, and the electric motor 30 drives the fan 34 torotate. As denoted by the arrows in FIG. 9, airflow produced by the fan34 would enter into the electric motor casing 33 from the airflowchannel 2121 and then be exhausted out from the air outlets 332.

As illustrated in FIG. 2, the tool housing assembly 50 is disposed witha circuit board 93 therein, and the circuit board 93 can achieve anelectrical connection between the electric motor 30 and the battery pack40. The circuit board 93 is disposed inside the first housing 51 andlocates on the front of the electric motor 30. That is, in the directionof the longitudinal axis S1 of the trimming blade 10, the circuit board93, the electric motor 30, the battery pack 40 and sequentially arrangedin that order; or in the direction of the longitudinal axis S1 of thetrimming blade 10, the circuit board 93, the electric motor 30 and thesecond housing 52 are sequentially arranged in that order. As shown inFIG. 9, the tool housing assembly 50 is formed with an air inlet 512, asdenoted by the arrows in FIG. 9, airflow produced by the fan 34sequentially flows through the air inlet 512, the circuit board 93, theelectric motor 30 and the air outlets 332.

As illustrated in FIG. 10 and FIG. 11, the electric motor 30 includes astator assembly 31 and a rotor assembly 32. The rotor assembly 32 of theelectric motor 30 is accommodated in the electric motor casing 33. Theelectric motor device includes the electric motor casing 33, theelectric motor 30, the fan 34 and a wind guide hood 35. The rotorassembly 32 is rotatable with respect to the stator assembly 31 and theelectric motor casing 33. The rotor assembly 32 is connected with thetransmission mechanism 20, and the rotor assembly 32 rotates to drivethe transmission mechanism 20. The fan 34 rotates along with the rotorassembly 32 of the electric motor 30. Commonly used electric motors 30have many kinds, such as a direct current (DC) motor 30 and analternating current (AC) motor 30. In particular, the electric motor 30is an outer rotor electric motor and more specifically is an outer rotorbrushless DC motor. The fan 34 is formed on or fixedly connected to therotor assembly 32. That is, the fan 34 may be directly formed by therotor assembly 32, or as an individual/separate part installed and fixedonto the rotor assembly 32. Furthermore, the fan 34 is fixedly connectedto the rotor assembly 32. In particular, the fan 34 is a centrifugalfan.

During the electric motor 30 is working, the fan 34 rotates along withthe rotor assembly 32 and brings airflow to move, and in particular therotor assembly 32 drives the fan 34 to rotate. The electric motor 30 isaccommodated in the electric motor casing 33, so that it is extremelyeasy to cause the airflow to spin around inside the electric motorcasing 33 and cannot leave the electric motor casing 33, which wouldaffect the cooling of the electric motor 30. In order to increasecooling efficiency, furthermore, the hedge trimmer 100 further includesthe wind guide hood 35, the wind guide hood 35 locates inside theelectric motor casing 33 and is fixed to the electric motor casing 33and further is stationary relative to the electric motor casing 33. Thewind guide hood 35 includes airflow shield portions 351, and the airflowshield portions 351 are for stopping airflow produced by the fan 34whirling within the electric motor casing 33. The airflow shieldportions 351 are disposed between an inner wall of the electric motorcasing 33 and the fan 34. More specifically, the airflow shield portions351 are located in a circumferential direction of rotation of the rotorassembly 32. The airflow shield portions 351 interrupt the whirling ofthe airflow in the electric motor casing 33, so as to promote theairflow to scatter and thereby increase cooling efficiency.

The electric motor casing 33 is formed with the air outlets 332. Theairflow shield portions 351 and the air outlets 332 are staggeredlyarranged in the circumferential direction of an axis of rotation of thefan 34. Specifically, the phase “staggeredly arranged” means that anarrangement in the circumferential direction of the axis of rotation ofthe fan 34 sequentially is the airflow shield portion 351, the airoutlet 332, the airflow shield portion 351 and the air outlet 332. Inthe circumferential direction of the rotation of the rotor assembly 32,the air outlets 332 and the airflow shield portions 351 are connected.The airflow shield portions 351 and the air outlets 332 are basicallyaligned in the axial direction of the axis of rotation of the fan 34. Inthe axial direction of the rotor assembly 32, the air outlets 332 andthe fan 34 have approximately equal heights.

The number of the airflow shield portions 351 is greater than or equalto 2, and at least two of the plurality of airflow shield portions 351are symmetrical with respect to the axis of rotation of the fan 34. Thewind guide hood 35 further includes a connecting portion 352, and theconnecting portion 352 is connected with the plurality of airflow shieldportions 351. At least two airflow shield portions 351 are connected bythe connecting portion 352. The connecting portion 352 is fixed onto thetop of the electric motor casing 33.

For an outer rotor electric motor, when a gap between the rotor assembly32 and the electric motor casing 33 is excessively large, most ofairflow would flow through the surface of the electric motor 30, but theairflow passing through the interior of the electric motor 30 is small,so that the cooling effect is poor. In order to reduce the gap betweenthe electric motor 30 and the electric motor casing 33, the wind guidehood 35 further includes a surrounding portion 353, and the surroundingportion 353 is disposed surrounding the rotor assembly 32. Thesurrounding portion 353 and the connecting portion 34 are located at twosides of the fan 34 respectively. The surrounding portion 353 is formedwith a buckle 3531, and the buckle 3531 is connected with the electricmotor casing 33.

When a gap between the surrounding portion 353 and the electric motor 30is excessively small, the cooling effect at the outer surface of therotor assembly 32 becomes poorer, resulting in degraded coolingefficiency. When the gap between the surrounding portion 353 and theelectric motor 30 is excessively large, the amount of airflow passingthrough the interior of the electric motor 30 becomes less, which alsocauses the cooling effect of the electric motor 30 to be poor.Furthermore, the gap between the surrounding portion 353 and theelectric motor 30 is greater than or equal to 0.3 mm and smaller than orequal to 3mm. Preferably, the gap between the surrounding portion 353and the electric motor 30 is greater than or equal to 0.5 mm and smallerthan or equal to 1.5 mm.

The basic principles, main features and advantages of the invention havebeen shown and described above. It should be understood to the skilledperson in the art that the above embodiments do not limit the inventionin any form, and any technical solution obtained in the way ofequivalent replacement or equivalent transformation ought to be withinthe scope of protection of the invention.

What is claimed is:
 1. A hedge trimmer comprising: an electric motor,the electric motor comprising a stator assembly and a rotor assembly; atransmission mechanism for being driven by the electric motor; a batterypack for supplying power to the electric motor; a trimming blade forbeing driven by the transmission mechanism to perform a shearing motion;an electric motor casing for accommodating the rotor assembly of theelectric motor; a tool housing assembly for facilitating thetransmission mechanism and the electric motor casing to be combined intoa whole; a first handle connected to the tool housing assembly andlocated between the trimming blade and the electric motor; a secondhandle connected to the tool housing assembly; and a transmission casingfor accommodating the transmission mechanism; wherein the transmissioncasing is exposed outside the tool housing assembly, the battery pack ismounted to the tool housing assembly and positioned adjacent to thesecond handle, the tool housing assembly includes a first material partwhich at least is made of a first material, the electric motor casingincludes a second material part which at least is made of a secondmaterial, the second material part is at least partly exposed outsidethe tool housing assembly, and a thermal property of the second materialis stronger than a thermal property of the first material.
 2. The hedgetrimmer as claimed in claim 1, wherein the first material is plastic andthe second material is metal.
 3. The hedge trimmer as claimed in claim1, wherein the transmission casing is at least partly made of a metalmaterial.
 4. The hedge trimmer as claimed in claim 1, wherein the secondmaterial part is exposed outside the tool housing assembly from one sideand the transmission casing is exposed outside the tool housing assemblyfrom an opposite side.
 5. The hedge trimmer as claimed in claim 1,wherein the transmission casing comprises a transmission casing mainbody formed with an accommodating chamber and a plurality oftransmission casing ribs outwardly protruding from the transmissioncasing main body, each two transmission casing ribs forms an airflowchannel therebetween, and the airflow channel extends substantiallyalong a direction parallel to an axis of the electric motor.
 6. Thehedge trimmer as claimed in claim 5, wherein the electric motor casingis disposed with a fan therein, the electric motor casing is formed withair outlets, and airflow produced by the fan enters into the electricmotor casing from the airflow channel and is then exhausted out from theair outlets.
 7. The hedge trimmer as claimed in claim 6, furthercomprising a circuit board disposed in the tool housing assembly andwherein the tool housing assembly is formed with an air inlet wherebyairflow produced by the fan sequentially flows through the air inlet,the circuit board, the electric motor and the air outlets.
 8. The hedgetrimmer as claimed in claim 1, wherein the tool housing assemblycomprises a first housing and a second housing, the first housing isformed or connected with the first handle, the second housing is formedor connected with the second handle, and the battery pack is combined tothe second housing.
 9. The hedge trimmer as claimed in claim 8, whereinthe first housing and the second housing respectively comprise a firstrotation connection part and a second rotation connection part formaking them be rotatably connected about a rotation axis such that thesecond housing has a first rotation position and a second rotationposition relative to the first housing and a plane perpendicular to therotation axis and a plane perpendicular to a longitudinal axis of thetrimming blade are obliquely intersected.
 10. The hedge trimmer asclaimed in claim 10, wherein in the plane perpendicular to thelongitudinal axis of the trimming blade the first rotation connectionpart and the electric motor are located at a same side of the trimmingblade.
 11. A hedge trimmer comprising: an electric motor, the electricmotor comprising a stator assembly and a rotor assembly; a transmissionmechanism for being driven by the electric motor; a trimming blade forbeing driven by the transmission mechanism to perform a shearing motion;an electric motor casing for accommodating the rotor assembly of theelectric motor; a tool housing assembly for facilitating thetransmission mechanism and the electric motor casing to be combinedtogether; a first handle connected to the tool housing assembly andlocated between the trimming blade and the electric motor; and a secondhandle connected to the tool housing assembly; wherein the electricmotor is located between the first handle and the second handle, thetool housing assembly includes a first material part which at least ismade of a first material, the electric motor casing includes a secondmaterial part which at least is made of a second material, the secondmaterial part is at least partly exposed outside the tool housingassembly, and a thermal property of the second material is stronger thana thermal property of the first material.
 12. The hedge trimmer asclaimed in claim 11, wherein the first material is plastic and thesecond material is metal.
 13. The hedge trimmer as claimed in claim 11,wherein the hedge trimmer further comprises a transmission casing foraccommodating the transmission mechanism and the transmission casing isexposed outside the tool housing assembly.
 14. The hedge trimmer asclaimed in claim 13, wherein the transmission casing is at least partlymade of a metal material.
 15. The hedge trimmer as claimed in claim 14,wherein the second material part is exposed outside the tool housingassembly from one side and the transmission casing is exposed outsidethe tool housing assembly from an opposite side.
 16. The hedge trimmeras claimed in claim 14, wherein the transmission casing comprises atransmission casing main body formed with an accommodating chamber and aplurality of transmission casing ribs outwardly protruding from thetransmission casing main body, each two transmission casing ribs formsan airflow channel therebetween, and the airflow channel extendssubstantially along a direction parallel to an axis of the electricmotor.
 17. The hedge trimmer as claimed in claim 16, wherein theelectric motor casing is disposed with a fan therein, the electric motorcasing is formed with air outlets, and airflow produced by the fanenters into the electric motor casing from the airflow channel and isthen exhausted out from the air outlets.
 18. The hedge trimmer asclaimed in claim 16, further comprising a circuit board disposed in thetool housing assembly and wherein the tool housing assembly is formedwith an air inlet whereby airflow produced by the fan sequentially flowsthrough the air inlet, the circuit board, the electric motor and the airoutlets.
 19. The hedge trimmer as claimed in claim 11, wherein the hedgetrimmer further comprises a battery pack for supplying power to theelectric motor, the tool housing assembly includes a first housing and asecond housing, the first housing is formed or connected with the firsthandle, the second housing is formed or connected with a second handle,and the battery pack is combined to the second housing.
 20. The hedgetrimmer as claimed in claim 19, wherein the first housing and the secondhousing respectively comprises a first rotation connection part and asecond rotation connection part for making them be rotatably connectedabout a rotation axis such that the second housing has a first rotationposition and a second rotation position relative to the first housing, aplane perpendicular to the rotation axis and a plane perpendicular to alongitudinal axis of the trimming blade are obliquely intersected, and,in the plane perpendicular to the longitudinal axis of the trimmingblade, the first rotation connection part and the electric motor islocated at a same side of the trimming blade.